Process for molding rubber articles



Dec. 8, 1925 1,564,310

F. C. JONES PROCESS FOR MOLDING RUBBER ARTICLES Filed May 1!.5, 1922 Patented Dec. 8,

- UNIT-ED s rain- 1s,

PATENT OFFICE.-

ronnxcn manna JONES, OF LONDON, ENGLAND;

PROCESS FOR IOLIING RUBBER ARTICLES,

Application and, ray is, 192 2. serial No. 501,130.

To all it may concern:

Be it known that I, Fonnron Cinemas JONES, a subject of the King'of Great Britain and Ireland, and a resident of London, 5 England, have invented a certain new and useful Improvement in Processes for Moldin'g Rubber Articles, of which the following is a specification.

My invention relates to the manufacture of rubber articles commonly known as dipped goods, such as teats, syringes, tubing, bulbs and the like, and has for its object a simple and. expeditious method of producing such articles without any seam-or mold mark.

luti'on is treated with sulphur dioxide and hydrogen sulphide) or by any other suitable process, wherem the gel substantially shrinks when drying out. This solution "is.

molded on to a core, the essence of the inv'ention residingrin allowing a gel ofthe type specified to shrink on to -a core. The gel 's preferably pouredlinto, a mold whose internal surface ,has' a suitable configuration somewhat as the external surface of the article to be finished, but-is largerg 1 An alternative mode of vvarying the resultant sectional configuration of the molded articleis hereinafter described.

The mold is adapted to receive a core which is removed with the el formed thereon. The size of the space ,tween the core and the internal surface of the mold is so proportioned that sufiicient rubber is obtained on the core to provide for the. sub- '1 4 stance ofthefinished article. The core with its coating of rubber is then set aside to dry and jlcontract and then the 'molded article, which has been shrunk on to the core, may be removed therefrom. Y T

materially assisted, ad device also being combined with meansto facilitate the removal of thecore and gel from the mold.

Such centering device is particularly aplicable to articlessuch as teats, wherein it is desirable tomold a pin hole atthe to and according thereto I construct a s'mal aperture 0 central of the base of the mold a, and also form a recess d central of the tip of the core 6, the aperture and recess being.-

coaxial when the core is positioned in the mold, I mount the core detachably, by a transverse pin a through the core spindle (which is mounted in a dead-central aperture in the cover f), in the said cover f, and the latter-snugly fits into the mouth of the mold-a. When the gel solution is poured intothe mold and the core a slender pin g is inserted throu h the aperture, through the gel, and into t e recess d of the core. When readyfor removal of the core, the pin 0 is extracted and the'aperture in the mold utilized for theaccommodation of H the nozzle of a water, steam, compressed air,- or other device to assist removal of the core. Any suitable means v may be employed for this purpose, and I show simply a recess h to accommodate said nozzle. v

With'a mold and core of this -description I may desire to form a contracted neck towards the top of the molding, and so that the enlargement in the'iniddle of the molding may be removed from the mold I insert a removable ring 5 in the top of the mold t6 form the contracted neck. Said rlng i has a central orifice to slide over the stem of the core 6 and a plurality of small passages j to allow passage of'solution therethrough.

' The mold a'mfay be formed of somewhat resilient material such as, rubber, or-an neck;

suitable cellulose or other compound, ,wi

a flexible neck. .Or it may be constructed vice w erein thefcentering of the core is In a modification, the inner contour of the A ,di ammatic cross-sectionqaof such 'inold an core is shown in the accompany mold member .a need not necessarily be i drawing. Y shaped to determine the outer configuration nthe dra g, a is the mold, and b the of 'the resultant molding, but such config-. core.- w i uration may be obtained, as also a varying 4 50 In molding of this description it-is essen= thickness. of the molded article, by pouring different layers of strata of the gel solution of various strengths of solution. That is to say, by way of example, if a bottom quantity- 'of an eight per cent solution is first poured in, then' an upperfportlon of a 12 per-cent tial that the core 6 be exactly centered to the mold a, otherwise the resultant article presents defects.

The' resent invention provides also a deno solution, the latter will dry out, when shrunk, thicker than the former and with a pronounced exterior bulge.

In a further manner of carrying out the invention, I may use a mold made of fusible metal, gelatine, aper, or other destructible substance capab e of being removed in its entirety from the shaped gel after any intricate or other shape has been formed. For instance, a collodion mold could be filled .witli solution, core inserted, and after the gel had 'set, such collodion cover could be broken or dissolved off, leaving the shaped gel to shrink on to the core.

The method of molding rubber or rubberconta-ining articles consisting of pouring layers of self-vulcanizing rubber-containing solutions of difierent strength into the space between an exterior mold and an interior core to obtain requisite contours and thicknesses of the resulting molded article,

and allowing the same to gel while confinedwithin said space.

In testimony whereof I have aflixedmy 25 signature hereto this 10th day of April 1922.

FORDYCE CHARLES 'JoNEs. 

